CHXII06:GENERAL PRINCIPLES AND PROCESSES OF ISOLATION OF ELEMENTS
321209
From the Ellingham graphs on carbon, which of the following statements is false?
1 \(\mathrm{\mathrm{CO}_{2}}\) is more stable than \(\mathrm{\mathrm{CO}}\) at less than \(\mathrm{983 \mathrm{~K}}\).
2 \(\mathrm{\mathrm{CO}}\) reduces \(\mathrm{\mathrm{Fe}_{2} \mathrm{O}_{3}}\) to \(\mathrm{\mathrm{Fe}}\) at less than 983 \(\mathrm{\mathrm{K}}\).
3 \(\mathrm{\mathrm{CO}}\) is less stable than \(\mathrm{\mathrm{CO}_{2}}\) at more than \(\mathrm{983 \mathrm{~K}}\).
4 \(\mathrm{\mathrm{CO}}\) reduces \(\mathrm{\mathrm{Fe}_{2} \mathrm{O}_{3}}\) to \(\mathrm{\mathrm{Fe}}\) in the reduction zone of Blast furnace.
Explanation:
Below \(\mathrm{983 \mathrm{~K}, \Delta G^{o}}\) for the formation of \(\mathrm{\mathrm{CO}_{2}}\) is more negative than \(\mathrm{\Delta G^{o}}\) for the formation of \(\mathrm{\mathrm{CO}}\), so \(\mathrm{\mathrm{CO}_{2}}\) is more stable. At temperature above \(\mathrm{983 \mathrm{~K}, \Delta G^{o}}\) formation of \(\mathrm{\mathrm{CO}}\) is more negative than \(\mathrm{\Delta G^{o}}\) formation of \(\mathrm{\mathrm{CO}_{2}}\), so \(\mathrm{\mathrm{CO}}\) is more stable. So statement (3) is false. \(\mathrm{\Delta G^{o}}\) formation of \(\mathrm{\mathrm{CO}_{2}}\) from \(\mathrm{\mathrm{CO}}\) is more negative than \(\mathrm{\Delta G^{o}}\) formation of \(\mathrm{\mathrm{Fe}_{2} \mathrm{O}_{3}}\). This means that \(\mathrm{\mathrm{Fe}_{2} \mathrm{O}_{3}}\) can be reduced by \(\mathrm{\mathrm{CO}}\) below \(\mathrm{1073 \mathrm{~K}}\).
